Conventional combined sensors for detecting angular velocity and acceleration are generally formed of angular velocity sensors for detecting angular velocity and acceleration sensors for detecting acceleration.
Therefore, in order to detect angular velocity and acceleration at the same time, an electronic device is required to have a plurality of angular velocity sensors and a plurality of acceleration sensors mounted on the substrate.
In general, an angular velocity sensor detects angular velocity by vibrating a detection element that can be formed in different shapes such as tuning-fork-shaped, H-shaped, or T-shaped, and by electrically detecting distortion of the angular velocity detection element caused by the Coriolis force. An acceleration sensor has weight parts and detects acceleration by making an acceleration detection element compare the acceleration before and after the movement of the weight parts. A combined sensor includes, for example, an angular velocity sensor and an acceleration sensor so as to detect angular velocity and acceleration at the same time.
These angular velocity sensors, acceleration sensors, and combined sensors are positioned along the respective axes of an attitude control system or a navigation system used in motor vehicles or other mobile objects.
Such a conventional technique related to the present invention is shown, for example, in Patent Documents 1 and 2 below.
In the aforementioned structure, the angular velocity sensors and the acceleration sensors are individually mounted on the substrate in such a manner as to be positioned along the respective axes for detecting angular velocity or acceleration. This requires a large mounting area, thus preventing the miniaturization of the combined sensor.
Patent Document 1: Japanese Patent Unexamined Publication No. 2001-208546
Patent Document 2: Japanese Patent Unexamined Publication No. 2001-74767